Thermoelectric Coolers (TECs) are solid state semiconductor devices that utilize the Peltier effect to transfer heat from one side of the device to the other, thereby creating a cooling effect on the cold side of the device. One example of a thermoelectric cooling device 10 is illustrated in FIG. 1. Notably, as used herein, a thermoelectric cooling device consists of a single N-type leg and a single P-type leg (i.e., is a two-leg device), whereas a thermoelectric cooling module includes many thermoelectric cooling devices connected in series. As such, the general term “thermoelectric cooler” or TEC is used herein as referring to either thermoelectric cooling devices or thermoelectric cooling modules.
As illustrated in FIG. 1, the thermoelectric cooling device 10 includes an N-type leg 12, a P-type leg 14, a top conductive metal layer 16, and a bottom conductive metal layer 18. The N-type leg 12 and the P-type leg 14 are formed of a thermoelectric material (i.e., a semiconductor material having good thermoelectric properties). In order to effect thermoelectric cooling, an electrical current is applied to the thermoelectric cooling device 10 as shown. The direction of current transference in the N-type leg 12 and the P-type leg 14 is parallel to the direction of heat transference in the thermoelectric cooling device 10. As a result, cooling occurs at the top conductive metal layer 16 by absorbing heat at the top surface of the thermoelectric cooling device 10 and releasing heat at the bottom surface of the thermoelectric cooling device 10. One example of a thermoelectric module 20 is illustrated in FIG. 2. As illustrated, the thermoelectric module 20 includes multiple thermoelectric cooling devices 10 connected in series. These multiple thermoelectric cooling devices 10 are packaged within a single thermoelectric module 20.
While thermoelectric cooling devices 10 and thermoelectric cooling modules 20 have been used in various cooling applications, conventionally, they have not been used for refrigeration due to, among other things, poor efficiency as compared to that of vapor-compressors. Recently, there have been many advances in both thermoelectric materials and heat transfer systems based on thermoelectric cooling devices and modules. As a result of these advances along with the many benefits of thermoelectric refrigeration over conventional vapor-compression refrigeration, thermoelectric refrigeration is primed to challenge vapor-compression refrigeration in both residential and commercial applications.
However, there remains a need to further improve the efficiency of thermoelectric cooling devices and modules.